From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id E45726008F0 for ; Wed, 19 May 2010 11:35:21 -0400 (EDT) Date: Wed, 19 May 2010 08:32:15 -0700 (PDT) From: Linus Torvalds Subject: Re: Unexpected splice "always copy" behavior observed In-Reply-To: Message-ID: References: <20100518153440.GB7748@Krystal> <1274197993.26328.755.camel@gandalf.stny.rr.com> <1274199039.26328.758.camel@gandalf.stny.rr.com> <20100519063116.GR2516@laptop> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Miklos Szeredi Cc: npiggin@suse.de, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, peterz@infradead.org, fweisbec@gmail.com, tardyp@gmail.com, mingo@elte.hu, acme@redhat.com, tzanussi@gmail.com, paulus@samba.org, linux-kernel@vger.kernel.org, arjan@infradead.org, ziga.mahkovec@gmail.com, davem@davemloft.net, linux-mm@kvack.org, akpm@linux-foundation.org, kosaki.motohiro@jp.fujitsu.com, cl@linux-foundation.org, tj@kernel.org, jens.axboe@oracle.com List-ID: On Wed, 19 May 2010, Miklos Szeredi wrote: > > Another limitation I found while splicing from one file to another is > that stealing from the source file's page cache does not always > succeed. This turned out to be because of a reference from the lru > cache for freshly read pages. I'm not sure how this could be fixed. It should be fixed by saying "you can't always just move the page". Copying is not evil. Complexity to avoid copies is evil. Linus -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org